溶血葡萄球菌多药耐药基因型分析

Multidrug Resistance Genotype among Clinical Isolates of Staphylococcus haemolyticus

目的研究溶血葡萄球菌对苯唑西林、庆大霉素和红霉素的多药耐药机制。方法琼脂稀释法测定3种抗菌药物对63株溶血葡萄球菌的最低抑菌浓度(MIC),PCR技术检测mecA、aac(6′)+aph(2″),ermA、ermB、ermC和msrA/msrB耐药基因。结果62株耐甲氧西林溶血葡萄球菌(MRSH)均携带mecA基因,50株耐庆大霉素溶血葡萄球菌均携带aac(6′)+aph(2″)基因,红霉素耐药基因以msrA/msrB基因最常见(58.7%),其次ermC基因(31.7%);43株多药耐药菌中,最常见3种耐药基因为mecA、aac(6′)+aph(2″)和msrA/msrB(58.1%)或ermC基因(20.9%),另8株(18.6%)同时携带mecA、aac(6′)+aph(2″)、ermC和msrA/msrB 4种耐药基因。结论mecA、aac(6′)+aph(2″)、msrA/msrB和ermC基因是溶血葡萄球菌对苯唑西林、庆大霉素和红霉素产生多药耐药的主要机制。

OBJECTIVE To investigate the prevalence of multidrug resistance （MDR） mechanisms of Staphylococcus haemolyticus against oxacillin, gentamycin and erythromycin. METItODS Agar dilution method was performed to detect the minimal inhibition concentration （MIC） of 3 antimicrobial agents against 63 strains of S. haemolyticus, and the resistance genes of mecA, aac（6＇）＋ aph（2＇＇）, ermA, ermB, ermC and msrA/msrB were investigated by PCR in all clinical isolates. RESULTS mecA Gene was detected in 62 isolates of meticillin-resistant S. haemolyticus （MRSH）, and aac （6＇）＋aph（2＇＇） gene was found in 50 isolates resistant to gentamicin, and the most prevalence erythromycin resistance gene in S. haemolyticus was msrA/msrB （58. 7%）, followed by ermC （31.7 %）. Among the 43 MDR strains, the more commonly encountered three genes were mecA, aac（6＇）＋ aph （2＇＇） and msrA/msrB （58. 1%）or ermC （20.9%）,and 8 isolates （18.6%） were found harboring four genes of mecA, aac （6＇）＋aph （2＇＇）, ermC and msrA/msrB. CONCLUSIONS The mecA, aac （6＇）＋aph （2＇＇）, msrA/msrB and ermC genes are main resistance mechanisms against oxacillin, gentamicin and erythromycin in mutidrug resistant S. haernolyticus.